


The Great Hogwarts Library Heist

by merriman



Category: Ocean's 8 (2018)
Genre: Alternate Universe - Hogwarts, Don't copy to another site, Gen, Heists, Libraries
Language: English
Status: Completed
Published: 2018-12-22
Updated: 2018-12-22
Packaged: 2019-09-24 15:44:55
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,716
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17103425
Author URL: https://archiveofourown.org/users/merriman/pseuds/merriman
Summary: You know what Hogwarts has? Besides a whole lot of moving staircases and a hat that sings? Books. Lots of very valuable books. And sixth year Slytherin Lou Miller has a plan to steal some of them. Or borrow some of them. Really, it's not her plan at all. But Lou is very good at making plans happen, once she knows what they are.





	The Great Hogwarts Library Heist

**Author's Note:**

  * For [booksareourlove](https://archiveofourown.org/users/booksareourlove/gifts).



> Thank you so very much for this wonderful prompt. I do hope my house choices for the characters all work well enough. I've included some reasoning behind them in the notes at the end.

Lou was seated at the far end of the Slytherin table during the opening feast. Sure, she was a sixth year, not seventh, but none of the seventh years were going to argue about her being there. They all owed her too much to snipe at her. Or she had good dirt on them. Greaves, in particular, could go hang for all she cared. He'd been quiet as she took a seat, though, leaving her to greet some of the younger members of their house.

At the next table over Lou watched as one of the Ravenclaws had already broken out an Exploding Snap deck and was trying to get some of the second years to play cards with her while they waited for the firsties to come in from the lake. One of them took her up on it and Lou watched closely. This particular girl had been on her radar since the previous year when she'd managed to get detention three times for sneaking out of Ravenclaw Tower after hours. Lou knew this because Lou herself had been out of the Slytherin dungeons after hours, but Lou had the sense not to get caught.

At the Ravenclaw table, the second year was playing fair. Well. That wasn't going to go well for him, Lou could see that right away. The owner of the deck had already slipped two cards up the sleeve of her robe and Lou wondered if she had some sort of compartment in there, or a sticking charm. Interesting idea. She made a mental note to look into it later - and to keep an eye on that Ravenclaw. She could be useful.

When the poor, hapless second year lost the game in a spectacular fashion - earning both himself and his classmate some severe looks from the faculty table - Lou turned her attention to the Hufflepuffs. She'd spent the train ride with Rose, but then, their families were friends so no one could comment on that one. Rose wasn't paying attention to anything around her. She was focused on some project or another she had in her lap. It was probably the self-darning socks she'd been working on. It was some sort of independent study she'd gotten permission to work on over summer holidays and as far as Lou could tell, she had yet to get them to work. Something about wool being resistant to magic? Lou couldn't bring herself to care much aside from making a note of _that_ in case she ever needed to charm a sheep or something. 

She didn't even bother looking over at the Gryffindors. She didn't have to. They were so noisy, welcoming their new Quidditch captain and cheering and going on like they owned the place. Honestly, it was exhausting. She wasn't sure how anyone in that house got anything done.

But then the professors were hushing everyone and the Headmistress was standing up and the great doors opened and in came all the first year students, led by Professor Longbottom. Lou watched them closely. There might be a few promising new faces in the crowd.

The sorting went as usual, with another song from the hat - Lou wondered if it repeated songs every seven years. Who would know, outside of the professors? There were a handful of younger siblings, including the younger sister of a Ravenclaw student Lou had some passing dealings with. Good to know smarts ran in the family.

* * *

"Have you ever met Daphne Kluger?" one of the new Slytherins asked Lou later that night in the Slytherin common room.

Lou shrugged. 

"Once. Her parents had a party and my parents dragged me along. She's nice enough if you like vapidity."

The first years had clustered around her and a couple of the other older students in the house after the feast. Lou had her legs up over the arm of her favorite armchair in the common room. It was grey and had probably once been velvet, but there was no charming it back to its old self. Too many students had sat in it over the years. Lou herself had mended one of the legs once, after a particularly involved argument between two fourth years over who deserved the better grade in Charms. They'd both been beaten out by some Gryffindor swot so it hadn't mattered in the end.

"What's the easiest class?" one of them asked. Lou figured she'd either know their names or have given them nicknames by the end of the week. 

"None of them are easy," she told them, swinging her legs around to set her feet on the floor. "Look, you'll do well and not embarrass the House, or we'll have words, got it?"

"She's not even a prefect," she heard one of them whisper to another. She gave him a wide grin and leaned in over the heads of two of the others.

"No. I'm not. So I don't have to care about the rules, now, do I?" she said. "Better get to bed, firsties. You've got History of Magic first thing in the morning and Professor Binns is a ghost, so he doesn't have much sympathy for things like oversleeping. Don't lose us points on the first day of classes if you can help it."

* * *

It wasn't hard slipping out after the rest of the dorm was asleep. Lou had perfected it well back in her second year at the school. There was a secret exit that went from the common room to an upper hallway that, as far as Lou had discovered, held only closets full of spare Hogwarts robes. She had plans for those robes. Eventually. Before she graduated, certainly.

The trick to moving around the castle at night was to not care of you got lost. If you cared too much the castle seemed to know it and you'd be turned around so much you'd end up back at your dorm before you knew it. So Lou just walked, certain she would arrive where she needed to be, which was a disused faculty break room she'd discovered along with a friend during her fourth year. They'd used it for late night games of chess for a while, but now it was almost exclusively used for Lou's network of friends to meet and pass along messages and contraband items, like the latest batch of Weasley's Wizard Wheezes that she was handing over tonight. 

"You're late," Tammy said as she entered. Lou rolled her eyes and pulled the Weasley's parcel out of her pocket, then tapped it with her wand to enlarge it again. She handed it to Tammy, who immediately started to unpack it and do an inventory.

"Had to wait for a staircase," Lou said as she draped herself over one of the chairs, then propped her feet up on a table. "Rose coming?"

"No. Rose is busy with that sock nonsense. I keep telling her to cut her losses but she wants that extra credit." Tammy didn't even look up as she spoke and Lou was sure that she also hadn't lost track of how many Skiving Snackboxes she'd counted so far.

"Well, I'll need her here tomorrow night. Her, and that Ravenclaw third year. Constance."

That did make Tammy look up. "You've got a plan already?"

Lou smiled. "Not exactly," she said. "But I know who does."

"Oh, speaking of which," Tammy said, reaching into an inner pocket of her bathrobe and pulling out a piece of parchment. "She's got a message for you."

Lou unfolded the parchment and sighed. It was blank, of course. She tapped it with her wand and whispered the password, then waited while the message took shape on the page. She read through it twice, then set the parchment on fire and let it burn to ash, which she swept into one hand and then tipped out the window and into the breeze.

"Who else are we going to need?" Tammy asked as she finished up her inventory and re-shrunk the bag so she could carry it back to the Hufflepuff dorm.

"Don't ask me," Lou said. "I'm not the one with the plan. I just make it happen. Ask her. We'll meet here tomorrow night."

* * *

The first years lost them twenty points on the first day of classes. But Lou had accounted for that in the odds and she'd also counted on the Gryffindors losing more. Oddly, the Ravenclaws lost the most, but then this year's crop of geniuses also seemed to be clever at getting into trouble. Lou knew she was going to lose a few Sickles on that one, but she rather liked the Ravenclaws better for it.

Of course, they'd also gained points that day, with the rest of the Slytherins working extra hard to make up for whatever the first years lost. Lou was sitting in her favorite chair, looking over the point tallies and the payout calculations. If only she could get Arithmancy credit for this.

"Lou!" one of her classmates called from the entrance. "There's some Ravenclaw girl here to talk to you."

Lou got up out of her seat and ambled over to the entrance. When she stepped through the doorway she saw Constance standing there, idly shuffling her cards while she waited.

"What do you want?" Lou asked. 

"I hear you're the person to talk to if I want to put something down on house points?" Constance said. "Is that right?"

Lou allowed her a tiny smirk. So Constance was checking on her first? Good idea.

"Yeah, that's right," Lou told her. "Rules are you can't bet on your own house and minimum is one Galleon. You in?"

"Two Galleons on Hufflepuff losing more than fifteen tomorrow."

"Specific, but not too specific," Lou said. "I like it. Okay. You're on the list."

"Cool." Constance nodded and turned around to walk away. "See you later."

* * *

That night Lou was careful to be the first one to the meeting room. She transfigured one of the chairs into something a little more comfortable and took a seat to wait. She'd gotten another message during the day and made certain that she had everything they'd need. Well. Everything they'd need that night.

Tammy and Rose arrived about two minutes after her, Tammy leading Rose in and sitting her down. Rose had a pair of knitting needles with her that clacked together on their own once she set them on the table. 

"I had to bring them," she said. "I finally got the wool to take the charm, but I've got to knit them from scratch or the darning won't work later on."

"Sure," Lou said, nodding even as she was turning her attention to Constance, who was slipping through the door just behind them. "Hey, have a seat. No card games tonight."

Constance just shrugged. "Fine. Hey, what did I make on that bet?"

"We settle up in the morning," Lou told her. "But you came out ahead."

"Who else is coming?" Tammy asked as she pulled a chair up to the table and got out some parchment. Lou could see that it was a mostly finished essay. Tammy got out a quill and some ink and started in where she'd left off.

Lou left her to it, not bothering to answer as another one of her chosen crew came through the door.

"Hey, this the right place?" 

"If you're looking for the midnight astronomy lecture, it's on the other side of the castle," Constance told her. "Good to see you, Leslie."

"Nine Ball," Leslie said. "Call me Leslie again and I'll short sheet your bed. Don't test me, Connie."

Constance laughed, then shifted to make room on the bench she'd sat down at.

Lou got up from her seat and held up her hands for attention. They still had a couple yet to come, but for now? They could get started. Besides, she knew the last two would be late. They were never on time for anything that wasn't an actual prank.

"So what's this all about?" Tammy asked. "If it's going to take too much time, I'm out. I have NEWTS to study for and an essay to finish."

"Merlin, you should be in our house," Leslie - no, Nine Ball - said. "Is she for real?"

Lou sighed. "Very real. But no, Tammy, I'm sure you'll have plenty of time."

"Of course she will." From the door behind them came another voice as the last two members of their little crew arrived. Tammy didn't look surprised and didn't bother to turn around and see who it was. She already knew, of course, ferrying notes between Lou and Debbie all the time. Everyone else, on the other hand, seemed somewhat shocked to see Gryffindor's golden girl walk through the door, followed by one of the Gryffindor prefects.

"Merlin's beard," Constance muttered, looking like she'd forgotten her Ancient Runes homework one too many times. "I hate detention…"

"No one's getting detention," Debbie said, strolling around the table to join Lou at the head, while Amita, the prefect, primly took a seat next to Tammy. "Everyone, this is Amita, I'm Debbie, and we're going to pull off a prank like you've never seen."

* * *

Convincing everyone to join in was easy enough. Amita had been in as soon as Debbie had mentioned it to her, that much Lou knew already. The Ravenclaws were in if only for the challenge of it. The Hufflepuffs? Well. Tammy was in because she knew it would pay off. Rose was in because they'd been friends for years outside of school and she never said no to Debbie and Lou. She hadn't said no their first year when they'd all been sorted into different houses and Debbie and Lou had told her their plan of acting like they barely knew each other, and she hadn't said no to any of the schemes they'd come up with since.

After the rest of the group had headed off to their dorms, Debbie and Lou stayed behind to talk. They hadn't really seen each other since getting back to school. Even over the summer they played it close, not associating much at social events their families were both at, not getting together in obvious places like Diagon Alley. After all, part of the whole game was that no one knew they were best friends. No one knew they'd come up with their best pranks together. And if one of them got caught, well, the other wouldn't have to pay. Who would ever associate them with each other, after all? And if someone from this little crew did? Well, they could pay them back in kind.

"So. What's this really about, and don't tell me it's about the Restricted Section," Lou said. All Debbie had given her was a vague proposal involving a lot of coded phrases Lou hadn't bothered to try and decipher.

"Oh, but that's the beauty," Debbie said, leaning back and resting her legs across Lou's lap. "It _is_ about the Restricted Section."

"Deb, look. I know you. I know us. This might fool Tammy and it might fool those two Ravenclaws - though I don't know about Nine Ball. She's sharper than she lets on. But it won't fool me. We don't just go after books to pass tests and we don't just put fakes in place to cause a ruckus." After all, if you needed to cheat to pass tests you weren't worth Lou's time. She wasn't going to judge herself any less harshly. And while reorganizing the Restricted Section was an amusing prospect, it wasn't something she had expected Debbie to put this much thought into.

Debbie just smiled at Lou and Lou sighed. That smile was evil. How Deb had convinced the hat to put her in Gryffindor, Lou still didn't know. But it did mean they had eyes in all four houses now. Ravenclaw had always been the question, but between Constance and Nine Ball, she figured they had a solid in now.

"So we steal some books and put fakes in their places," Lou said. "We've got Amita to make the fakes, Rose to make the concealment charms, Constance to grab them and put the fakes in place, Nine Ball to figure out the cataloguing in that maze of a library, Tammy's got the materials for the fakes. You and I have the charms for the fakes so they'll behave…"

"No," Debbie said. "You have the charms. I've got to be nowhere near this. I'm the Quidditch captain. I'm up for Head Girl next year if I play my cards right."

Lou sighed. "Whatever, sure. I'll take care of the charms. But what, oh mistress of strategy, do we do about Madam Pince?"

"We get a distraction," Debbie said. "You and Rose know Daphne Kluger, right?"

* * *

Daphne was in. She didn't know she was in, but she was in. Tammy had assured Debbie and Lou that she could maneuver Daphne into asking for Madam Pince's help in the library and she could get her to keep Madam Pince's attention for long enough.

Lou trusted Tammy, but she wasn't sure she trusted Tammy this much. So she needed a backup plan. And she needed to figure out what Debbie was really after. She'd finally gotten her best friend in the entire world to admit that she was planning to use the books they were grabbing to sell test answers to unwitting students, but Lou had the list of books they were grabbing. They weren't the sorts of books they'd get anything useful out of. One was a dry tome full of minutiae about the collection of dragon teeth. One was apparently a book that showed you the answer to a question posed to it the day before, which was interesting, and potentially useful, but not much of a marketing plan. The last was a book of maps for places that no longer existed. In fact, the more Lou looked into this particular book, the more she was certain that the places in it weren't in their realm of existence. One notation she found in a book that referenced it mentioned that the cartographer who'd made the book had disappeared after its publication and it was presumed he had gotten stuck in Faerie or some such place.

Interesting stuff. Not the sort of stuff they could sell. And besides, Lou had finally figured out one of the code phrases in Debbie's original plan and she was about 99% sure it meant that Debbie was planning on putting at least two of the three originals back.

So yes, Lou had some homework to do on top of the homework she had to do for classes. Sixth year was a right pain when it came to homework. It was as if every professor had leveled up in difficulty and expected their students had done the same over the holidays.

* * *

"Ready?" Lou asked Constance, who nodded. Everyone was in place. Amita was seated at a carrel in an out of the way corner. Tammy was with Daphne, working her up to a whole host of questions to ask the librarian that should take them on a circuitous path through the library, keeping them well out of the way of the rest of the crew as they worked. Nine Ball had already figured out the cataloguing of both the main library and the Restricted Section, though Lou knew she'd also had to consult her little sister on some of the finer points. But they'd gotten it done. Rose had gotten all the concealment charms done and placed on their robes. Constance had helped out there, showing Rose how she kept cards stuck to the insides of her sleeves and then Rose strengthening the charm to work on books. Debbie was out of the way, apparently, and Lou was standing by to set things in motion and charm the fakes. She had a few other ideas of her own, but she'd have to see what happened once things were moving.

Nothing ever moved quite how you predicted, no matter how well you planned. They couldn't empty the library, after all, and they couldn't account for the movements of other students of professors. This could all still go south very quickly.

Lou took a seat near the entrance of the library, waiting for Tammy and Daphne to come in. When she heard Daphne's unmistakable voice she stood up and started walking. If all went well, she'd be right in place in time to get the books to Amita, then the fakes to Constance. If all didn't go well, she was in the right place to get everyone out and be the only one left holding the bag. 

Really, it was almost honorable, what she was doing. She should have been in Gryffindor with Debbie.

* * *

Things didn't go perfectly. They never did. Daphne got distracted mid-question at one point and Madam Pince almost abandoned her in disgust, but then she'd gotten back on track and led her in the opposite direction with a question about books on divination.

Two first year Slytherins had almost walked right into them in the middle of the hand-off, but then they'd caught sight of Lou's disapproving look and turned back the way they'd come. If Lou was lucky, they'd just think she'd thought they were making too much noise in the library. Which they had been, to be fair.

When the books were copied well enough to pass a cursory inspection and charms had been laid on them to behave themselves until, well, until they weren't meant to behave themselves anymore, they'd gotten them back to the Restricted Section and Amita had gone about getting some of the really interesting charm work off the originals.

Half an hour later, the library was evacuated when three books in the Restricted Section apparently escaped from their tethers and started flying about the place, breaking through a rusted latch and into the main library. They swooped down at students heads, making off with not a few hats, headbands, and quills. Not to mention some parchment and several pages out of other books. 

Lou evacuated along with everyone else, not looking at anyone except for Tammy and Daphne, whom she joined on their walk down the stairs. 

"I really did want to check out that book on jewel divination," Daphne sighed. "Oh well. Maybe Madam Pince can get it away from that horrible dragon book."

"Maybe," Lou said, shrugging.

"Think we'll have any luck convincing Professor Binns to give us an extra day?" a Slytherin first year asked Lou as he caught up with her.

"No," Lou said. "But I'm sure you can figure it out. We've got a small library of our own in the dungeons."

The first year ran off down the stairs and Lou followed, nodding to Tammy and Daphne as they parted ways.

* * *

They waited three nights before getting back together. The chaos in the library had been attributed to several conflicting charms degrading too close to each other and interacting poorly. The books had been re-tethered and the rusted latch on the screen they'd gotten through had been repaired. But still. It didn't do to make it too obvious that they'd been involved. Any of them.

When Lou got to the meeting room, Constance was already there, playing Exploding Snap with Tammy. Lou could have warned Constance, but hey, she had to learn some time that you just didn't want to con some people. Tammy could give as good as she got. Better, even.

Nine Ball looked to be asleep in the corner, but a twitch of her fingers near her wand when Lou opened the door gave her away. Lou didn't call her out for it. If no one else had figured her out, Lou wasn't going to ruin her fun.

Lou had just sat down when Debbie and Amita arrived. Amita had a large satchel over her shoulder, which she set down on the table and unpacked before taking her seat. 

"Where's Rose?" Constance asked Tammy, just as the door opened again.

Rose walked in, followed by Daphne Kluger, who grinned brightly at them.

"Oh wow, this is fun!" Daphne said, giving them all a little wave. "I was just saying to Rose that this was going to be fun, wasn't I?"

"She was," Rose sighed as she sat down next to Tammy. "I'm sorry, you guys, I couldn't shake her. I'm no good at that."

"It's fine," Debbie said. "I figured she'd follow you."

Lou had figured she would too. Daphne put on a good act, but it was mostly for show. Sometimes it paid to be underestimated. Like, for example, when you had to ask a librarian a bunch of very foolish questions.

"So, what do we have?" she asked them. "I mean, you have to have had a reason for getting all those books."

"Just three," Debbie told her. "And we don't have them."

Everyone at the table turned to face Debbie and Lou, who had gone to stand next to her.

"We don't?" Tammy asked. Tammy didn't get angry that often, but Lou could see that it was on the horizon. "What do you mean we don't have them?"

"We don't have them," Lou repeated what Debbie had said. "But we have the charms that made them tick and we have some very useful information out of them."

"Such as?" Constance asked. "What do we need with dragon teeth anyhow? I'm not going near enough to a dragon to get its teeth."

Neither was Lou, but that wasn't the point.

"That's not the point," Debbie said. "The point is that the dragon book made for a useful and convincing distraction. The answer book, on the other hand, we managed to reverse engineer some of the charmwork on. So we can charm something else to do something similar. We don't need the book if we have the charm that makes it work."

On her other side, Amita held up a sheaf of parchment sheets and smiled. "I got top marks in Advanced Charms last year. Professor Flitwick's been showing me how to work a charm backwards to map it out."

"What about the map book?" Nine Ball asked. "I don't really want to deal with the Fae. And you can't tell me you copied all those maps that fast."

"Oh no," Amita said, shaking her head. "But it did have this fascinating charm for showing movement on maps. It's like muggle phones do, but magic, and without the phone."

"Well this is all great," Tammy said. "But you said we'd get something useful out of this. Something we could all use!"

"And we did," Debbie assured her. She reached into her robe and pulled out a folded piece of parchment. As she did, Lou pulled out another. She saw Debbie glance at her and offered a smirk in response. Of course she'd figured out what Debbie was looking for. James Potter was a Gryffindor, sure, but Al Potter was a Slytherin. And he'd made mention of a map his father had used as a boy at Hogwarts. Lou was good at Arithmancy, sure, but she hadn't needed that to put two and two together and get four - four being the prototype maps for the one Harry Potter apparently still owned.

Debbie and Lou both unfolded their maps and tapped them with their wands.

"We solemnly swear we are up to no good," they said. Everyone gathered around the table to look as the maps revealed themselves. There were differences to them. Lou's was missing all the dorms but Gryffindor, and some names seemed to be stuck in the walls. Debbie's had the dorms, but it faded out every few seconds as people moved around. These were clearly works in progress, hidden in relatively plain sight in a book of maps.

"We can reverse engineer the charms, right?" Debbie asked Amita.

Nine Ball and Constance were already whispering to each other and making notes. Amita was tracking a stray line of ink and nodding to herself. 

"Oh yes," Amita murmured. "Then it's one for each of us?"

"One for each house," Debbie told them. "We're in this together."

"See?" Daphne was saying to Rose. "I told you this looked like fun!"

**Author's Note:**

> Lou - Slytherin because she's devious and practical about it and willing to do what needs doing to get ahead.  
> Debbie - Gryffindor because while she's a total con artist, she's also loyal to her friends and family and gutsy enough to go ahead with her plans. I also wanted to use James and Al being in Gryffindor and Slytherin, respectively, to give them plausible info on the map.  
> Amita - Gryffindor because there is honor among thieves and she has it.  
> Tammy - Hufflepuff because I suspect she could talk the hat around to it by pointing out that she just wants a good quiet life.  
> Rose - Hufflepuff because I can't possibly imagine her anywhere else.  
> Nine Ball - Ravenclaw because I can't possibly imagine her anywhere else. She likes an intellectual puzzle.  
> Constance - Ravenclaw because she is clever and I wanted her in the same house as Nine Ball.  
> Daphne - Hufflepuff because she just wants to have fun and make friends. If the means to that are pranks, then that's the way she'll go about it.


End file.
